C# 从树视图中删除父节点

标记：

<asp:TreeView ID="TreeView2" runat="server" ImageSet="Inbox" Width="200px">
                            <ParentNodeStyle Font-Bold="True" />
                            <HoverNodeStyle Font-Underline="True" ForeColor="#5555DD" />
                            <SelectedNodeStyle Font-Underline="True" HorizontalPadding="0px" VerticalPadding="0px"
                                ForeColor="#5555DD" />
                            <Nodes>
                                <asp:TreeNode Text="New Request" Value="Home" NavigateUrl="~/NewRequest.aspx" ToolTip="New Request">
                                </asp:TreeNode>
                                <asp:TreeNode NavigateUrl="~/MyCertificates.aspx" Text="My Certificates" Value="Help"
                                    ToolTip="My Certificates"></asp:TreeNode>
                                    <asp:TreeNode NavigateUrl="~/MyRequest.aspx" Text="My Requests" Value="Help"
                                    ToolTip="My Request"></asp:TreeNode>
                                    <asp:TreeNode NavigateUrl="~/AdminRights.aspx" Text="Admin" Value="admin only"
                                    ToolTip="Admin"></asp:TreeNode>
                                <asp:TreeNode NavigateUrl="~/Reneval.aspx""
                                    Text="Download Root Certificate" Value="RootCertificate" ToolTip="Download Root Certificate">
                                </asp:TreeNode>
                            </Nodes>
                            <NodeStyle Font-Names="Calibri" Font-Size="8pt" ForeColor="DarkGray" HorizontalPadding="5px"
                                NodeSpacing="0px" VerticalPadding="0px" />
                            <LeafNodeStyle ForeColor="Black" />
                        </asp:TreeView>

tnObj

始终为空。

此行错误：

 <asp:TreeNode NavigateUrl="~/AdminRights.aspx" Text="Admin" Value="admin only"
                                ToolTip="Admin"></asp:TreeNode>

 <asp:TreeNode NavigateUrl="~/AdminRights.aspx" Text="Admin" Value="admin only"
                                ToolTip="Admin"></asp:TreeNode>

TreeView.FindNode Method: Retrieves the TreeNode object in the TreeView control at the specified value path.